Dr Herve Fevrier is the EVP and COO of Xtera Communications Prior to this assignment, where, previously, he was in charge of photonics development as well as marketing, business development and sales. Prior to Xtera, Dr Fevrier served Alcatel in a wide variety of posts including Director of the Photonic Networks research unit, Senior Director for DWDM Product Development Worldwide, VP & GM Optical Networks Alcatel USA and VP Network and Product Strategy Alcatel Optics. Dr Herve Fevrier received his doctoral degree in Physics from the University of Paris; he holds a Physics engineering degree from the Ecole Centrale de Paris.

Article abstract

Mobile broadband, cloud computing and video services grab our attention because they hold the promise of transforming the way that we live, work and play. But each of these applications relies on the evolution of the wire-line network to be successful since it is the combination of services over mobile and wire-line networks that will have the greatest impact upon availability and usability. The evolution is underway with the increased popularity of Raman amplification and the emergence of 100 Gb/s line rates.

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Wire-line network Mobile Broadband growth is the rave of the industry and will be an important source of revenue growth for service providers. According to a report by Ovum, “By the end of 2015 there will be three billion mobile broadband connections worldwide serving 2.4 billion people”. Many of these users will take advantage of iPhones, iPads and other smart mobile devices that give them access to information anytime and anywhere. This provides new revenue opportunities for service providers who appear to be losing wire-line customers. The popularity of mobile, though, does not mean that the wire-line network is going away or becoming less important. In fact, mobile broadband services benefit from a far-reaching, high quality, wire-line network. Service providers that can converge mobile and wire-line services can take advantage of consumers growing appetite for high-bandwidth applications and the associated service markets that are still in the early stages of growth. In addition to mobile broadband services, service providers with high capacity wire-line networks will see opportunities in the emerging cloud and video services arena. The continued evolution of the wire-line network must remain a key part of the strategy to growing these services. According to Ovum, by the end of 2015, 2.6 billion people will still have access to a wire-line broadband connection at home, and 1.4 billion will be using both wire-line and mobile broadband services. These broadband users will overwhelm a network that is not able to scale to support the new emerging services. The need for a scalable wire-line network was identified in the late 90s, driven by reports that the Internet was doubling every six to nine months. The phenomenal Internet growth rate, led some to forecast that the wire-line network could not keep pace. The worry was that the Internet traffic would outpace the available capacity of the network. Service providers all around the world aggressively deployed more fibre to support the forecasted growth. Now as the new emerging services, mobile broad-band, cloud and video services, gain in popularity, along with the continued growth of the Internet, the fibre based wire-line network must scale as well. Thankfully, the technology exists to support this growth for years to come. The technology is dense wave division multiplexing (DWDM). DWDM is the core technology that transforms a fibre so that instead of carrying a single wavelength, it carries multiple wavelengths. So for example, instead of carrying a single wavelength at 10 Gb/s, it can carry N x 10 Gb/s. Transmitting multiple wavelengths provides increased capacity and flexibility. The increase in capacity allows more information (data, graphics, video) to be transmitted faster. The use of multiple wavelengths provides the flexibility to deliver information to different locations and to group data that has similar transmission characteristics. DWDM and its associated technologies, reconfigurable optical add/drop multiplexers (ROADM) for example; continue to provide capacity growth, flexibility to support various bandwidth-hungry applications and to drive down networking cost. The line rates that are supported by DWDM also continue to increase. Just a few years ago, the maximum practical line rate was 10 Gb/s. The highest fibre capacity could be achieved by using a DWDM system with all-Raman amplification (in-line, all-optical, distributed signal amplification for all-band wavelength coverage), providing 240 X 10 Gb/s or 2.4 Tb/s on a single fibre. Today, new systems are available that support multiple wavelengths at 10 Gb/s, 40 Gb/s and 100 Gb/s. Coupling 100 Gb/s with the latest Raman based DWDM system continues to provide the highest capacity in the industry. Using the latest Raman system with 100G, service providers are now able to achieve 150 X 100Gb/s, i.e. 15 Tb/s on a single fibre. There are many applications enabled by DWDM and ROADM based wire-line networks. These applications will enrich the lives of consumers and simplify the life of business owners. It might be helpful to take a quick look at how evolution of the wire-line network supports growth of mobile broadband, cloud and video services. Links between mobile and wire-line networks Mobile networks use radio waves to transfer information to and from mobile devices and towers or antennas. However, these networks rely on line of sight transmission. They have a typical range of .5 to 5 miles. Given the right circumstances they can reach up to around 25 miles. However, all mobile networks eventually connect to a wire-line network. Mobile networks are a quick way of providing communications to emerging areas, but they must tie to a wire-line network to interface to the Internet and to the rest of the world. When broadband is transmitted over mobile devices, the range of transmission is shortened. Broadband information is normally transferred for the greatest distance possible using high-speed wire-line networks (generally optical networks) and then converted for transmission by mobile networks.Cloud computing The recent global recession served as a catalyst to promote change in the way we live, work, and play. Businesses are turning to technology to make them more efficient. One area that is emerging is cloud computing. For many, the idea of cloud computing holds the promise of transforming the way that we create, store, access and share information. Cloud computing not only holds the promise of helping businesses to cut costs, but also could change the structure of business itself in both the short term and long term. However, the success of cloud computing could very well depend on the ability of the communication network to handle the enormous increase in traffic that cloud computing could generate. Figure 2: Cloud networking The goal of cloud computing is to simplify the process of creating, storing, accessing, and sharing information while dramatically lowering costs. This goal will be accomplished by shifting the service and cost of high-power computers and storage to a third party. The network of computers at the third party remote location is typically referred to as the cloud. Hardware and software demands on the user’s side decrease. The user’s computer only needs the ability to run the cloud computing systems interface software, by using a Web browser or other simple interface. The third party provides cloud services, such as hardware maintenance, software updates, back-ups, transfers, etc. While this simplifies the activity at business locations, it increases the load on the network. If the network does not provide fast easy access to the information in the cloud, or if the network is not reliable, cloud networking and its associated services will not be successful. Video based applications Video applications are also increasing rapidly and threatening to overwhelm communication networks. Real-time video is growing in importance, and video communication traffic is accelerating. According to Cisco’s visual networking index, “Video-on-demand (VoD) traffic will double every two and a half years through 2014.” This growth provides both an opportunity and a challenge to communication service providers. Video applications require a lot of network bandwidth, but do not always provide a proportionate amount of revenue. The key for service providers is to create a high capacity, multi-use network, capable of handling a large number of diverse applications. Each application can be valued differently and the service provider will be able to charge accordingly. In addition, the network must be scalable. Initially, the network will be sized to minimize cost. As video services grow in popularity, the network can be scaled accordingly. Raman based DWDM networks provide a number of features which make them attractive for high-capacity multi-use. Systems using all-Raman based amplification can handle the highest number of wavelengths. This remains true even as service providers move to higher bit rates like 100 Gb/s. The additional wavelengths, not only can be used for additional capacity, they can be used to provide increased flexibility. They provide a greater degree of choice when deciding how to route services. As shown in figure 3, services are converged onto a common fibre, but have diverse starting and ending points. This is an important step in creating high-quality networks that support the different characteristics of various applications. In addition, DWDM networks using Raman amplification support longer delivery distances. Longer distances can be used to eliminate intermediate sites and thus improve the quality of the signal and drive down cost. Figure 3: High-capacity DWDM network ____________________________ We tend to hear a lot about emerging mobile-broadband services. This occurs because these services have the ability to transform the lives of people in emerging and established economies. Anytime, anywhere access to broadband services can both simplify and enrich our lives. But it is the combination of services over mobile and wire-line networks that will have the greatest impact. And to be successful, these services require a scalable wire-line network using technologies like Raman and 100 Gb/s to maximize capacity, reach longer distances and drive down the cost of providing services.